Autistic people are autistic all the time. Sometimes some difficulties fade into the background, then come back out again when someone is particularly stressed out. This is true across the board for sensory issues, communication issues, movement, and all kinds of other things. (This is also true for people with any other kind of disability).

The intermittent nature of some apparent difficulties can sometimes lead to them being misinterpreted as psychosomatic. They’re not. Everyone, autistic or not, has more trouble doing things that are hard for them when they’re experiencing significant stress. Some things are particularly hard for autistic people, and those things also get harder with stress.

This is how it actually works:

Doing the thing always takes a lot of effort

Putting in all that effort has become second nature

When you’re not exceptionally stressed, you might not notice the effort it takes consciously

When you *are* really stressed, you don’t have energy to do the thing in the ways you normally can

So you end up having more trouble than usual, and probably looking a lot more conspicuously disabled than usual

For instance, with motor issues:

For those of us with motor difficulties, moving smoothly and accurately takes more effort than it does for most people

This can become second nature, to the point that we don’t consciously notice how difficult it is

But it’s still there

And when you’re really stressed or overwhelmed, you may not have the energy to make yourself move accurately

So things you can normally do (eg: handwriting, not walking into walls, picking up objects, pouring water) might become awkward or impossible

That doesn’t mean you’re faking or somehow doing it on purpose

It just means that things are harder when you’re stressed

Or with sensory issues:

Living with sensory sensitivities means that a lot of things hurt

For the sake of doing things anyway, a lot of us build up a high pain tolerance

To the point that we may no longer consciously process things as pain even though they hurt

Ignoring pain takes a lot of energy

When we’re really stressed, we may not have the energy to ignore pain

And things we normally tolerate can be experienced as overloading or intolerably painful

That doesn’t mean we’re faking the pain to avoid something stressful, or that we’re somehow bringing it on ourselves.

It just means that everything is harder under stress, including tolerating pain

Or with communication:

Communication can be hard for a lot of us in varying ways

For some of us, being able to speak requires juggling a lot of things that are automatic for most people

Or being able to use words at all, including typing

For some of us, that’s true of understanding people when they talk to us

Or of knowing what words are at all

If someone can’t talk, understand or use words under stress, it doesn’t mean that they’re somehow faking it to avoid a difficult situation

It means that communication is hard, and stress makes everything harder

tl;dr Stress makes everything harder. For people with disabilities, that includes disability-related things, including things that we don’t normally seem to have trouble with. Sometimes we’re wrongly assumed to be doing on purpose or faking to avoid a difficult situation; it should actually be seen as an involuntary, normal, and expected physiological response to stress.